Secretary of State Marco Rubio has a new job title: interim national security adviser.

President Donald Trump announced the development on social media Thursday after firing his previous national security adviser, Michael Waltz. Waltz’s ouster followed a bombshell report in The Atlantic about him inadvertently adding a reporter to a group chat to discuss a bombing campaign in Yemen.

Trump said Waltz’s new role in his administration will be as the U.S. ambassador to the United Nations. Trump had previously offered the position to Rep. Elise Stefanik (R-N.Y.) but withdrew it over fears it might endanger Republicans’ slim majority in the House.

Rubio already had a lengthy list of responsibilities prior to today’s news. In addition to secretary of state, he’s also the acting administrator for U.S. Agency for International Development, and the acting national archivist.